Radio desk set



April 0- E. E. CLEMENT 1,754,880

RADIO DESK SET Original Fil ed Oct. 27. 1922 2 Sheets-Sheet 1 April 15, 1930.

E. E. CLEMENT RADIO DESK SET Original Filed Oct. 27. 1922 2 Sheets-Sheet 2 KID/0 I 1 IMPL/FV/IVG 751 [Pl/ONE OUTPUT Patented Apr. 15, 1930 UNITED STATES PATENT OFFICE EDWARD n. CLEMENT, or wnsnrireron, nrsrnicr or conurinrii, Assrenon 'ro EDWARD F. GOLLALDAY, or WASHINGTON, DISTRICT or COLUMBIA RADIO DESK SET Division of application Serial No. 681,992, filed December 21, 1923, which is a division of application Serial No. 597,422, filed Gc'tober 2?, 1322, issued as Patent No. 1,576,308. Divided and this application filed August 1, 1925. Serial No. 47,547.

This application is a division of my copending application, Serial No. 681,992, filed December 21, 1923, which is a divisionof application Serial No. 597,422, filed October 27,

1922, issued as Patent No. 1,576,308. The present invention relates to radio systems and more particularly to receiving sets.

The main object of the invention is to provide a light and compact receiving set, capahis of being moved about, within limits, at

the convenience of the user. A further object is to provide aset mechanically free but electrically connected so that movement of y the same will be unhampered as by conductor cords or similar mechanical connections.

Another object is to provide a combination set having both loud speaker and earphone attachments with automatic switchook control.

Other objects of the invention will be apparent from a perusal of the following specification and the drawings accompanying the same.

1 In the drawings,

Fig. 1 is a schematic diagram showing a central oifice and one subscr'ibers line with a subscribers station equipped with a radio desk set receiver.

Fig. 2 is a similar diagram of a modified form of a radio receiving apparatus for the central oifice for changing the wave length transmitted to the subscriber.

Fig. 3 is a front elevation of the subscribers desk set.

Fig. 4 is a side elevation of the same.

Fig. 5 is a modification in which the cord connection is dispensed with.

Fig. 5 is a modification of the form of Fig. 5 in which radio amplification is interposed between the line and the primary coil.

Fig: 5 is another modification of the form of Fig. 5 using inductive transmission of audio frequencies to the desk set.

Referring to the drawings, in Fig. 1, the apparatus to the left of the vertical dotted lines is situated at the central office, that to the right is at the subscribers station while the connection indicated between the dotted lines is the line connection.

The telephone exchange system assumed therein to be used in carrying out my inven-- tion is the standard Western Electric No. 1 switchboard circuit with the usual standard Western Electric substation apparatus. 1

The part of the usual telephone exchange system here shown comprises the subscribers substation apparatus A connected by conductors 1 and 2 to the conductors 3 and 4' of the line B terminating at the central oflice C through the wires 5 and 6 on multiple jacks 7. Radio broadcast from other stations is received at the telephone central station by the receiving or antenna circuit 8, from which the broadcast is relayed or amplified onto the wires 3i of the subscribers line circuit B through known or other suitable amplifying and coupling means such as the amplifying system indicated at 9 and the switch 10. Other switches such as 11 areconnected with the amplifier 9 in multiple with the switch 10 for the purpose of connecting to other subscribers lines. For broadcasting directly from the central office a radio transmitting circuit of' any known or other suitable form is provided at the central office, such as the radio transmitting circuit 12 with modulating transmitter 13 coupled by means of the coupling coil 14: to multiple switching means such as the plugs 15 and 16 through which the radio transmitting circuit may be connected with any subscribers line through local broadcast jacks such as the jack 1? multipled onto thesubscribers line extension 56.

Either relayed or local broadcast is put on to the subscribers lines at radio frequency and at sufficient amplitude to enable the audio frequencies to be segregated or detected at the subscribers substations with a simple detector set which may be of any known or the test coupling so that all the energy will go into the latter, although, if desired, the

ead phones may be permanently connected and t e test coupling simply connected in shunt when wanted.

To enable the reception at the subscribers substation to be supervised from the central oflice, a supervisory circuit 22 is provided at the central oflice arranged to be connected with any subscribers line through suitable switching means such as the plug 23 adapted to engage with jacks such as 2% connected in multiple to the subscribers line extension 5-6. The supervisory circuit 22 may be of any suitable type, preferably that used with the Western Electric No. 1 switchboard system, the essentials being that it contain means for calling the subscriber such as the ringing ke 25, and a listening and talking set 26 an listening key 27. The supervisory coupling 20 at the subscribers substation is pre era ly arranged to be normally disconnected from the line and to be connected therewith at will through a suitable switch such as 28. The operator may have a special radio listening set, as indicated at- 26 connected to the plug 23 through an amplifier 26 and key 27 of usual construction, so that the return currents through the line to central will be strengthened. Such ampli fiers or electron tube relays are well known and need no description. I believe this combination to be new and original with me.

In operation, broadcast is put onto the subscribers lines such as 34 at the central station C, either directly by means of the local set 12 or indirectly by means of the relay set 89 and a subscriber at substation A wishing to receive the broadcast listens in by means of the detector circuit 18 and radiophone 19. During the broadcasting if the supervisory operator desires to test the quality of reception at substation A he plugs in on the line at 2324 and depresses the ringing key 25 whereupon the subscriber at A is signalled in the usual manner. The subscriber at A responding is instructed to reverse switch 21 and close switch 28, which thereupon disconnects the audio circuit of the detector from the receivers 9 and connects it with the line extension 1-2 by way of conductors 29-30, coupler 20 and switch 28, from whence the circuit is extended over the line conductors 3-4, line extension 56, jack and plug connection 2423 and listening key 27 to the supervisory operators listening set 26. The operator now listening in on the reception at the subscribers substation can ascertain the quality thereof and finding it defective can judge of the cause of such defect. For example he can discern the efi'ects of static, induction from power lines, cross talk from telephone lines, loose connections, etc.

In Fig. 2, I have shown a radio receiving circuit 8*, connected to usual radio amplifier and detector apparatus 9% which in turn is connected to an audio amplifying set 9, connected to a modulator and transmitting set 9, having its output side terminating on switching means such as plugs for connection to line circuits. The principle involved herein is that of receiving at one wave length and relaying onto the subscribers lines at a different wave length. The transmitter 9 and the receiver 8-9 are capable of being separately tuned, in a manner well under stood in the art, which is important as an element in this invention, because all my subscribers instruments are standardized and fiat tuned, that is, all are permanently tuned on the same wave length, which is the normal transmitting wave length of the central oiiice to which they are connected for service. The range of tuning is immaterial.

In Figs. 3 and 4, I have shown a form of subscribers desk instrument embodying the elements 18, 19, 20, 21, and 28 of Fig. 1. The base 34 is hollow, and the detector set 18 with coupler 20, is arranged therein with suitable circuit connections through cords 4243 or through ordinary wiring. If cords are employed, the mutual capacity of the conductors must be neutralized or minimized so as not to interfere with reception of the high frequency waves by the detector set. On base 34 is erected a column 32 carrying a switchhook 31, controlling contacts within the column and shown in the diagram, Fig. 1, at 31. This hook when down disconnects the entire set from line, and when up connects the set through wires &243 to line. Two manual switches 21 and 28 are mounted on the base with contacts preferably within the same, to control the listening set connection to 19 and the cut-back to central at 29-30. A horn 33 is mounted on the upper end of the column, with coupling nipples 33 arranged on opposite side of its neck for receiving the two head phones 19 when the subscriber prefers to listen in that way. Tuning handles of any desired form may be also arranged on the outside of the base as shown at 18*.

The foregoing arrangement is flexible and will lend itself to various detailed forms of subscribers instruments. For example, the cord connections of the radio set 18-19 may be dispensed with, as indicated in Figure 5. The line connections 4243 here terminate in the primary coil 18 of which the secondary 18 is carried on the instrument, con veniently in the base thereof. Coil 18 may be enclosed in a casing as indicated in dotted lines, and the instrument adjusted with reference thereto either over it, or to one side. It is to be understood that the circuit of the coil 18 may be tuned in any desired way, as by a series variable condenser or by a fixed condenser, with taps off of the coil in accordance with well understood practice. The

Several instruments and several secondaries may be used if desired with a single primary. In this case I have shown a tube detector 18 with A and B batteries and tuning condenser all enclosed within the instrument body. Tubes suitable for this purpose are commercially available, and small batteries are also on the market, either storage cells or dry batteries. /Vhere more ample battery capacity is desired, separate batteries may be connected to the desk set through a cord of usual type as indicated atin Fig. 5. In any case the receiver 19 is connected to the instrument circuits through a cord, which for simplicity of illustration is omitted in Figs. 3 and 4, but is indicated in Fig. 5. The mechanical parts are numbered the same in Fig. 5 as in Figs. 3 and a, the outline only of the desk stand or casing being shown in dotted lines.

It is to be understood that radio or audio amplifying means, or both may be added to the receiving set without departing from the scope of my invention. Where the detached or loose coupled form of instrument is employed the arrangement of Fig. 5 may be used, where the radio amplification may be between the line connections 4243 and the primary winding 18 and audio amplification means may be mounted on or in the instrument unit. A further modification is that indicated in Fig. 5 which is accomplished by connecting to the line wires 42-43 a complete detector set including radio and audio amplifying tubes, detector coils and tuning devices, with the primary winding of an audio transformer or inductorium of any suitable form arranged the same as coil 18*. The instrument would then carry the secondary 18 of said inductorium, the receiver, and a wire connection to the receiver, only. Various other modifications will suggest themselves to those skilled in the art, and it is to be understood that I contemplate all such non-essential changes or modifications as fall fairly within the scope of the appended claims.

Having thus described my invention, which I claim is:

1. In combination with a wire circuit carrying modulated superaudio waves and terminating in a tuned and mechanically fixed primary coupling coil, a mechanically detached, movable and self-contained radiophone receiving set comprising a unitary standard and base, a detector therein, an amplifying horn thereon, a secondary cou pling coil therein, in a plane normally parallel with that of said primary coupling coil, circuit wires and connections mounted there in, an audio frequency receiver carried thereon and adapted to be connected with said amplifying horn, and a switch also carried thereon and having contacts included in said circuits, together with a source of current for the detector, the arrangement being such that the coil, detector, receiver, and horn are controlled as to their proper operative relations by the movement of said switch.

2. In combination with a wire circuit carrying modulated superaudio waves and terminating in a tuned primary coil mechanically fixed in a horizontal plane, a mechanically detached, freely movable, and self-contained radiophone desk set receiver comprising hollow base or support, a vertical hollow standard thereon, a detector in said standard, an amplifier horn mounted on said standard, an audio frequency receiver cooperating with said horn at the upper end of said standard, a secondary receiving loop or coupler coil in said hollow base, normally held horizontal and thereby adapted to receive from said fixed horizontal primary coil electromagnetic waves having a vertical magnetic component, a circuit connection between said coil and said audio frequency receiver, extending through said standard, and a switch thereon controlling said circuit.

In testimony whereof I hereunto affix my signature.

EDWARD E. CLEMENT. 

